/*
 * cmdgen.c - command-line form of PuTTYgen
 */

#define PUTTY_DO_GLOBALS

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>
#include <assert.h>
#include <time.h>
#include <errno.h>
#include <string.h>

#include "putty.h"
#include "ssh.h"

#ifdef TEST_CMDGEN
/*
 * This section overrides some definitions below for test purposes.
 * When compiled with -DTEST_CMDGEN (as cgtest.c will do):
 *
 *  - Calls to get_random_data() are replaced with the diagnostic
 *    function below (I #define the name so that I can still link
 *    with the original set of modules without symbol clash), in
 *    order to avoid depleting the test system's /dev/random
 *    unnecessarily.
 *
 *  - Calls to console_get_userpass_input() are replaced with the
 *    diagnostic function below, so that I can run tests in an
 *    automated manner and provide their interactive passphrase
 *    inputs.
 *
 *  - main() is renamed to cmdgen_main(); at the bottom of the file
 *    I define another main() which calls the former repeatedly to
 *    run tests.
 */
#define get_random_data get_random_data_diagnostic
char *get_random_data(int len, const char *device)
{
  char *buf = snewn(len, char);
  memset(buf, 'x', len);
  return buf;
}
#define console_get_userpass_input console_get_userpass_input_diagnostic
int nprompts, promptsgot;
const char *prompts[3];
int console_get_userpass_input(prompts_t *p, unsigned char *in, int inlen)
{
  size_t i;
  int ret = 1;
  for (i = 0; i < p->n_prompts; i++) {
    if (promptsgot < nprompts) {
      p->prompts[i]->result = dupstr(prompts[promptsgot++]);
    } else {
      promptsgot++; /* track number of requests anyway */
      ret = 0;
    }
  }
  return ret;
}
#define main cmdgen_main
#endif

struct progress {
  int phase, current;
};

static void progress_update(void *param, int action, int phase, int iprogress)
{
  struct progress *p = (struct progress *)param;
  if (action != PROGFN_PROGRESS)
    return;
  if (phase > p->phase) {
    if (p->phase >= 0)
      fputc('\n', stderr);
    p->phase = phase;
    if (iprogress >= 0)
      p->current = iprogress - 1;
    else
      p->current = iprogress;
  }
  while (p->current < iprogress) {
    fputc('+', stdout);
    p->current++;
  }
  fflush(stdout);
}

static void no_progress(void *param, int action, int phase, int iprogress)
{
}

void modalfatalbox(const char *p, ...)
{
  va_list ap;
  fprintf(stderr, "FATAL ERROR: ");
  va_start(ap, p);
  vfprintf(stderr, p, ap);
  va_end(ap);
  fputc('\n', stderr);
  cleanup_exit(1);
}

void nonfatal(const char *p, ...)
{
  va_list ap;
  fprintf(stderr, "ERROR: ");
  va_start(ap, p);
  vfprintf(stderr, p, ap);
  va_end(ap);
  fputc('\n', stderr);
}

/*
 * Stubs to let everything else link sensibly.
 */
void log_eventlog(void *handle, const char *event)
{
}
char *x_get_default(const char *key)
{
  return NULL;
}
void sk_cleanup(void)
{
}

void showversion(void)
{
  char *buildinfo_text = buildinfo("\n");
  printf("puttygen: %s\n%s\n", ver, buildinfo_text);
  sfree(buildinfo_text);
}

void usage(int standalone)
{
  fprintf(standalone ? stderr : stdout,
          "Usage: puttygen ( keyfile | -t type [ -b bits ] )\n"
          "                [ -C comment ] [ -P ] [ -q ]\n"
          "                [ -o output-keyfile ] [ -O type | -l | -L"
          " | -p ]\n");
  if (standalone)
    fprintf(stderr, "Use \"puttygen --help\" for more detail.\n");
}

void help(void)
{
  /*
   * Help message is an extended version of the usage message. So
   * start with that, plus a version heading.
   */
  printf("PuTTYgen: key generator and converter for the PuTTY tools\n"
         "%s\n",
         ver);
  usage(FALSE);
  printf("  -t    specify key type when generating (ed25519, ecdsa, rsa, "
         "dsa, rsa1)\n"
         "  -b    specify number of bits when generating key\n"
         "  -C    change or specify key comment\n"
         "  -P    change key passphrase\n"
         "  -q    quiet: do not display progress bar\n"
         "  -O    specify output type:\n"
         "           private             output PuTTY private key format\n"
         "           private-openssh     export OpenSSH private key\n"
         "           private-openssh-new export OpenSSH private key "
         "(force new format)\n"
         "           private-sshcom      export ssh.com private key\n"
         "           public              RFC 4716 / ssh.com public key\n"
         "           public-openssh      OpenSSH public key\n"
         "           fingerprint         output the key fingerprint\n"
         "  -o    specify output file\n"
         "  -l    equivalent to `-O fingerprint'\n"
         "  -L    equivalent to `-O public-openssh'\n"
         "  -p    equivalent to `-O public'\n"
         "  --old-passphrase file\n"
         "        specify file containing old key passphrase\n"
         "  --new-passphrase file\n"
         "        specify file containing new key passphrase\n"
         "  --random-device device\n"
         "        specify device to read entropy from (e.g. /dev/urandom)\n");
}

static int move(char *from, char *to)
{
  int ret;

  ret = rename(from, to);
  if (ret) {
    /*
     * This OS may require us to remove the original file first.
     */
    remove(to);
    ret = rename(from, to);
  }
  if (ret) {
    perror("puttygen: cannot move new file on to old one");
    return FALSE;
  }
  return TRUE;
}

static char *readpassphrase(const char *filename)
{
  FILE *fp;
  char *line;

  fp = fopen(filename, "r");
  if (!fp) {
    fprintf(
        stderr, "puttygen: cannot open %s: %s\n", filename, strerror(errno));
    return NULL;
  }
  line = fgetline(fp);
  if (line)
    line[strcspn(line, "\r\n")] = '\0';
  else if (ferror(fp))
    fprintf(stderr,
            "puttygen: error reading from %s: %s\n",
            filename,
            strerror(errno));
  else /* empty file */
    line = dupstr("");
  fclose(fp);
  return line;
}

#define DEFAULT_RSADSA_BITS 2048

/* For Unix in particular, but harmless if this main() is reused elsewhere */
const int buildinfo_gtk_relevant = FALSE;

int main(int argc, char **argv)
{
  char *infile = NULL;
  Filename *infilename = NULL, *outfilename = NULL;
  enum
  {
    NOKEYGEN,
    RSA1,
    RSA2,
    DSA,
    ECDSA,
    ED25519
  } keytype = NOKEYGEN;
  char *outfile = NULL, *outfiletmp = NULL;
  enum
  {
    PRIVATE,
    PUBLIC,
    PUBLICO,
    FP,
    OPENSSH_AUTO,
    OPENSSH_NEW,
    SSHCOM
  } outtype = PRIVATE;
  int bits = -1;
  char *comment = NULL, *origcomment = NULL;
  int change_passphrase = FALSE;
  int errs = FALSE, nogo = FALSE;
  int intype = SSH_KEYTYPE_UNOPENABLE;
  int sshver = 0;
  struct ssh2_userkey *ssh2key = NULL;
  struct RSAKey *ssh1key = NULL;
  unsigned char *ssh2blob = NULL;
  char *ssh2alg = NULL;
  const struct ssh_signkey *ssh2algf = NULL;
  int ssh2bloblen;
  char *old_passphrase = NULL, *new_passphrase = NULL;
  int load_encrypted;
  progfn_t progressfn = is_interactive() ? progress_update : no_progress;
  const char *random_device = NULL;

  /* ------------------------------------------------------------------
   * Parse the command line to figure out what we've been asked to do.
   */

  /*
   * If run with no arguments at all, print the usage message and
   * return success.
   */
  if (argc <= 1) {
    usage(TRUE);
    return 0;
  }

  /*
   * Parse command line arguments.
   */
  while (--argc) {
    char *p = *++argv;
    if (*p == '-') {
      /*
       * An option.
       */
      while (p && *++p) {
        char c = *p;
        switch (c) {
        case '-':
          /*
           * Long option.
           */
          {
            char *opt, *val;
            opt = p++; /* opt will have _one_ leading - */
            while (*p && *p != '=')
              p++; /* find end of option */
            if (*p == '=') {
              *p++ = '\0';
              val = p;
            } else
              val = NULL;

            if (!strcmp(opt, "-help")) {
              if (val) {
                errs = TRUE;
                fprintf(stderr,
                        "puttygen: option `-%s'"
                        " expects no argument\n",
                        opt);
              } else {
                help();
                nogo = TRUE;
              }
            } else if (!strcmp(opt, "-version")) {
              if (val) {
                errs = TRUE;
                fprintf(stderr,
                        "puttygen: option `-%s'"
                        " expects no argument\n",
                        opt);
              } else {
                showversion();
                nogo = TRUE;
              }
            } else if (!strcmp(opt, "-pgpfp")) {
              if (val) {
                errs = TRUE;
                fprintf(stderr,
                        "puttygen: option `-%s'"
                        " expects no argument\n",
                        opt);
              } else {
                /* support --pgpfp for consistency */
                pgp_fingerprints();
                nogo = TRUE;
              }
            } else if (!strcmp(opt, "-old-passphrase")) {
              if (!val && argc > 1)
                --argc, val = *++argv;
              if (!val) {
                errs = TRUE;
                fprintf(stderr,
                        "puttygen: option `-%s'"
                        " expects an argument\n",
                        opt);
              } else {
                old_passphrase = readpassphrase(val);
                if (!old_passphrase)
                  errs = TRUE;
              }
            } else if (!strcmp(opt, "-new-passphrase")) {
              if (!val && argc > 1)
                --argc, val = *++argv;
              if (!val) {
                errs = TRUE;
                fprintf(stderr,
                        "puttygen: option `-%s'"
                        " expects an argument\n",
                        opt);
              } else {
                new_passphrase = readpassphrase(val);
                if (!new_passphrase)
                  errs = TRUE;
              }
            } else if (!strcmp(opt, "-random-device")) {
              if (!val && argc > 1)
                --argc, val = *++argv;
              if (!val) {
                errs = TRUE;
                fprintf(stderr,
                        "puttygen: option `-%s'"
                        " expects an argument\n",
                        opt);
              } else {
                random_device = val;
              }
            } else {
              errs = TRUE;
              fprintf(stderr, "puttygen: no such option `-%s'\n", opt);
            }
          }
          p = NULL;
          break;
        case 'h':
        case 'V':
        case 'P':
        case 'l':
        case 'L':
        case 'p':
        case 'q':
          /*
           * Option requiring no parameter.
           */
          switch (c) {
          case 'h':
            help();
            nogo = TRUE;
            break;
          case 'V':
            showversion();
            nogo = TRUE;
            break;
          case 'P':
            change_passphrase = TRUE;
            break;
          case 'l':
            outtype = FP;
            break;
          case 'L':
            outtype = PUBLICO;
            break;
          case 'p':
            outtype = PUBLIC;
            break;
          case 'q':
            progressfn = no_progress;
            break;
          }
          break;
        case 't':
        case 'b':
        case 'C':
        case 'O':
        case 'o':
          /*
           * Option requiring parameter.
           */
          p++;
          if (!*p && argc > 1)
            --argc, p = *++argv;
          else if (!*p) {
            fprintf(stderr,
                    "puttygen: option `-%c' expects a"
                    " parameter\n",
                    c);
            errs = TRUE;
          }
          /*
           * Now c is the option and p is the parameter.
           */
          switch (c) {
          case 't':
            if (!strcmp(p, "rsa") || !strcmp(p, "rsa2"))
              keytype = RSA2, sshver = 2;
            else if (!strcmp(p, "rsa1"))
              keytype = RSA1, sshver = 1;
            else if (!strcmp(p, "dsa") || !strcmp(p, "dss"))
              keytype = DSA, sshver = 2;
            else if (!strcmp(p, "ecdsa"))
              keytype = ECDSA, sshver = 2;
            else if (!strcmp(p, "ed25519"))
              keytype = ED25519, sshver = 2;
            else {
              fprintf(stderr, "puttygen: unknown key type `%s'\n", p);
              errs = TRUE;
            }
            break;
          case 'b':
            bits = atoi(p);
            break;
          case 'C':
            comment = p;
            break;
          case 'O':
            if (!strcmp(p, "public"))
              outtype = PUBLIC;
            else if (!strcmp(p, "public-openssh"))
              outtype = PUBLICO;
            else if (!strcmp(p, "private"))
              outtype = PRIVATE;
            else if (!strcmp(p, "fingerprint"))
              outtype = FP;
            else if (!strcmp(p, "private-openssh"))
              outtype = OPENSSH_AUTO, sshver = 2;
            else if (!strcmp(p, "private-openssh-new"))
              outtype = OPENSSH_NEW, sshver = 2;
            else if (!strcmp(p, "private-sshcom"))
              outtype = SSHCOM, sshver = 2;
            else {
              fprintf(stderr, "puttygen: unknown output type `%s'\n", p);
              errs = TRUE;
            }
            break;
          case 'o':
            outfile = p;
            break;
          }
          p = NULL; /* prevent continued processing */
          break;
        default:
          /*
           * Unrecognised option.
           */
          errs = TRUE;
          fprintf(stderr, "puttygen: no such option `-%c'\n", c);
          break;
        }
      }
    } else {
      /*
       * A non-option argument.
       */
      if (!infile)
        infile = p;
      else {
        errs = TRUE;
        fprintf(stderr,
                "puttygen: cannot handle more than one"
                " input file\n");
      }
    }
  }

  if (bits == -1) {
    /*
     * No explicit key size was specified. Default varies
     * depending on key type.
     */
    switch (keytype) {
    case ECDSA:
      bits = 384;
      break;
    case ED25519:
      bits = 256;
      break;
    default:
      bits = DEFAULT_RSADSA_BITS;
      break;
    }
  }

  if (keytype == ECDSA && (bits != 256 && bits != 384 && bits != 521)) {
    fprintf(stderr,
            "puttygen: invalid bits for ECDSA, choose 256, 384 or 521\n");
    errs = TRUE;
  }

  if (keytype == ED25519 && (bits != 256)) {
    fprintf(stderr, "puttygen: invalid bits for ED25519, choose 256\n");
    errs = TRUE;
  }

  if (keytype == RSA2 || keytype == RSA1 || keytype == DSA) {
    if (bits < 256) {
      fprintf(stderr,
              "puttygen: cannot generate %s keys shorter than"
              " 256 bits\n",
              (keytype == DSA ? "DSA" : "RSA"));
      errs = TRUE;
    } else if (bits < DEFAULT_RSADSA_BITS) {
      fprintf(stderr,
              "puttygen: warning: %s keys shorter than"
              " %d bits are probably not secure\n",
              (keytype == DSA ? "DSA" : "RSA"),
              DEFAULT_RSADSA_BITS);
      /* but this is just a warning, so proceed anyway */
    }
  }

  if (errs)
    return 1;

  if (nogo)
    return 0;

  /*
   * If run with at least one argument _but_ not the required
   * ones, print the usage message and return failure.
   */
  if (!infile && keytype == NOKEYGEN) {
    usage(TRUE);
    return 1;
  }

  /* ------------------------------------------------------------------
   * Figure out further details of exactly what we're going to do.
   */

  /*
   * Bomb out if we've been asked to both load and generate a
   * key.
   */
  if (keytype != NOKEYGEN && infile) {
    fprintf(stderr, "puttygen: cannot both load and generate a key\n");
    return 1;
  }

  /*
   * We must save the private part when generating a new key.
   */
  if (keytype != NOKEYGEN && (outtype != PRIVATE && outtype != OPENSSH_AUTO &&
                              outtype != OPENSSH_NEW && outtype != SSHCOM)) {
    fprintf(stderr,
            "puttygen: this would generate a new key but "
            "discard the private part\n");
    return 1;
  }

  /*
   * Analyse the type of the input file, in case this affects our
   * course of action.
   */
  if (infile) {
    infilename = filename_from_str(infile);

    intype = key_type(infilename);

    switch (intype) {
    case SSH_KEYTYPE_UNOPENABLE:
    case SSH_KEYTYPE_UNKNOWN:
      fprintf(stderr,
              "puttygen: unable to load file `%s': %s\n",
              infile,
              key_type_to_str(intype));
      return 1;

    case SSH_KEYTYPE_SSH1:
    case SSH_KEYTYPE_SSH1_PUBLIC:
      if (sshver == 2) {
        fprintf(stderr,
                "puttygen: conversion from SSH-1 to SSH-2 keys"
                " not supported\n");
        return 1;
      }
      sshver = 1;
      break;

    case SSH_KEYTYPE_SSH2:
    case SSH_KEYTYPE_SSH2_PUBLIC_RFC4716:
    case SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH:
    case SSH_KEYTYPE_OPENSSH_PEM:
    case SSH_KEYTYPE_OPENSSH_NEW:
    case SSH_KEYTYPE_SSHCOM:
      if (sshver == 1) {
        fprintf(stderr,
                "puttygen: conversion from SSH-2 to SSH-1 keys"
                " not supported\n");
        return 1;
      }
      sshver = 2;
      break;

    case SSH_KEYTYPE_OPENSSH_AUTO:
    default:
      assert(0 && "Should never see these types on an input file");
    }
  }

  /*
   * Determine the default output file, if none is provided.
   *
   * This will usually be equal to stdout, except that if the
   * input and output file formats are the same then the default
   * output is to overwrite the input.
   *
   * Also in this code, we bomb out if the input and output file
   * formats are the same and no other action is performed.
   */
  if ((intype == SSH_KEYTYPE_SSH1 && outtype == PRIVATE) ||
      (intype == SSH_KEYTYPE_SSH2 && outtype == PRIVATE) ||
      (intype == SSH_KEYTYPE_OPENSSH_PEM && outtype == OPENSSH_AUTO) ||
      (intype == SSH_KEYTYPE_OPENSSH_NEW && outtype == OPENSSH_NEW) ||
      (intype == SSH_KEYTYPE_SSHCOM && outtype == SSHCOM)) {
    if (!outfile) {
      outfile = infile;
      outfiletmp = dupcat(outfile, ".tmp", NULL);
    }

    if (!change_passphrase && !comment) {
      fprintf(stderr,
              "puttygen: this command would perform no useful"
              " action\n");
      return 1;
    }
  } else {
    if (!outfile) {
      /*
       * Bomb out rather than automatically choosing to write
       * a private key file to stdout.
       */
      if (outtype == PRIVATE || outtype == OPENSSH_AUTO ||
          outtype == OPENSSH_NEW || outtype == SSHCOM) {
        fprintf(stderr, "puttygen: need to specify an output file\n");
        return 1;
      }
    }
  }

  /*
   * Figure out whether we need to load the encrypted part of the
   * key. This will be the case if either (a) we need to write
   * out a private key format, or (b) the entire input key file
   * is encrypted.
   */
  if (outtype == PRIVATE || outtype == OPENSSH_AUTO || outtype == OPENSSH_NEW ||
      outtype == SSHCOM || intype == SSH_KEYTYPE_OPENSSH_PEM ||
      intype == SSH_KEYTYPE_OPENSSH_NEW || intype == SSH_KEYTYPE_SSHCOM)
    load_encrypted = TRUE;
  else
    load_encrypted = FALSE;

  if (load_encrypted && (intype == SSH_KEYTYPE_SSH1_PUBLIC ||
                         intype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
                         intype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH)) {
    fprintf(stderr,
            "puttygen: cannot perform this action on a "
            "public-key-only input file\n");
    return 1;
  }

  /* ------------------------------------------------------------------
   * Now we're ready to actually do some stuff.
   */

  /*
   * Either load or generate a key.
   */
  if (keytype != NOKEYGEN) {
    char *entropy;
    char default_comment[80];
    struct tm tm;
    struct progress prog;

    prog.phase = -1;
    prog.current = -1;

    tm = ltime();
    if (keytype == DSA)
      strftime(default_comment, 30, "dsa-key-%Y%m%d", &tm);
    else if (keytype == ECDSA)
      strftime(default_comment, 30, "ecdsa-key-%Y%m%d", &tm);
    else if (keytype == ED25519)
      strftime(default_comment, 30, "ed25519-key-%Y%m%d", &tm);
    else
      strftime(default_comment, 30, "rsa-key-%Y%m%d", &tm);

    random_ref();
    entropy = get_random_data(bits / 8, random_device);
    if (!entropy) {
      fprintf(stderr,
              "puttygen: failed to collect entropy, "
              "could not generate key\n");
      return 1;
    }
    random_add_heavynoise(entropy, bits / 8);
    smemclr(entropy, bits / 8);
    sfree(entropy);

    if (keytype == DSA) {
      struct dss_key *dsskey = snew(struct dss_key);
      dsa_generate(dsskey, bits, progressfn, &prog);
      ssh2key = snew(struct ssh2_userkey);
      ssh2key->data = dsskey;
      ssh2key->alg = &ssh_dss;
      ssh1key = NULL;
    } else if (keytype == ECDSA) {
      struct ec_key *ec = snew(struct ec_key);
      ec_generate(ec, bits, progressfn, &prog);
      ssh2key = snew(struct ssh2_userkey);
      ssh2key->data = ec;
      ssh2key->alg = ec->signalg;
      ssh1key = NULL;
    } else if (keytype == ED25519) {
      struct ec_key *ec = snew(struct ec_key);
      ec_edgenerate(ec, bits, progressfn, &prog);
      ssh2key = snew(struct ssh2_userkey);
      ssh2key->data = ec;
      ssh2key->alg = &ssh_ecdsa_ed25519;
      ssh1key = NULL;
    } else {
      struct RSAKey *rsakey = snew(struct RSAKey);
      rsa_generate(rsakey, bits, progressfn, &prog);
      rsakey->comment = NULL;
      if (keytype == RSA1) {
        ssh1key = rsakey;
      } else {
        ssh2key = snew(struct ssh2_userkey);
        ssh2key->data = rsakey;
        ssh2key->alg = &ssh_rsa;
      }
    }
    progressfn(&prog, PROGFN_PROGRESS, INT_MAX, -1);

    if (ssh2key)
      ssh2key->comment = dupstr(default_comment);
    if (ssh1key)
      ssh1key->comment = dupstr(default_comment);

  } else {
    const char *error = NULL;
    int encrypted;

    assert(infile != NULL);

    /*
     * Find out whether the input key is encrypted.
     */
    if (intype == SSH_KEYTYPE_SSH1)
      encrypted = rsakey_encrypted(infilename, &origcomment);
    else if (intype == SSH_KEYTYPE_SSH2)
      encrypted = ssh2_userkey_encrypted(infilename, &origcomment);
    else
      encrypted = import_encrypted(infilename, intype, &origcomment);

    /*
     * If so, ask for a passphrase.
     */
    if (encrypted && load_encrypted) {
      if (!old_passphrase) {
        prompts_t *p = new_prompts(NULL);
        int ret;
        p->to_server = FALSE;
        p->name = dupstr("SSH key passphrase");
        add_prompt(p, dupstr("Enter passphrase to load key: "), FALSE);
        ret = console_get_userpass_input(p, NULL, 0);
        assert(ret >= 0);
        if (!ret) {
          free_prompts(p);
          perror("puttygen: unable to read passphrase");
          return 1;
        } else {
          old_passphrase = dupstr(p->prompts[0]->result);
          free_prompts(p);
        }
      }
    } else {
      old_passphrase = NULL;
    }

    switch (intype) {
      int ret;

    case SSH_KEYTYPE_SSH1:
    case SSH_KEYTYPE_SSH1_PUBLIC:
      ssh1key = snew(struct RSAKey);
      if (!load_encrypted) {
        void *vblob;
        unsigned char *blob;
        int n, l, bloblen;

        ret =
            rsakey_pubblob(infilename, &vblob, &bloblen, &origcomment, &error);
        blob = (unsigned char *)vblob;

        n = 4; /* skip modulus bits */

        l = ssh1_read_bignum(blob + n, bloblen - n, &ssh1key->exponent);
        if (l < 0) {
          error = "SSH-1 public key blob was too short";
        } else {
          n += l;
          l = ssh1_read_bignum(blob + n, bloblen - n, &ssh1key->modulus);
          if (l < 0) {
            error = "SSH-1 public key blob was too short";
          } else
            n += l;
        }
        ssh1key->comment = dupstr(origcomment);
        ssh1key->private_exponent = NULL;
        ssh1key->p = NULL;
        ssh1key->q = NULL;
        ssh1key->iqmp = NULL;
      } else {
        ret = loadrsakey(infilename, ssh1key, old_passphrase, &error);
      }
      if (ret > 0)
        error = NULL;
      else if (!error)
        error = "unknown error";
      break;

    case SSH_KEYTYPE_SSH2:
    case SSH_KEYTYPE_SSH2_PUBLIC_RFC4716:
    case SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH:
      if (!load_encrypted) {
        ssh2blob = ssh2_userkey_loadpub(
            infilename, &ssh2alg, &ssh2bloblen, &origcomment, &error);
        if (ssh2blob) {
          ssh2algf = find_pubkey_alg(ssh2alg);
          if (ssh2algf)
            bits = ssh2algf->pubkey_bits(ssh2algf, ssh2blob, ssh2bloblen);
          else
            bits = -1;
        }
        sfree(ssh2alg);
      } else {
        ssh2key = ssh2_load_userkey(infilename, old_passphrase, &error);
      }
      if ((ssh2key && ssh2key != SSH2_WRONG_PASSPHRASE) || ssh2blob)
        error = NULL;
      else if (!error) {
        if (ssh2key == SSH2_WRONG_PASSPHRASE)
          error = "wrong passphrase";
        else
          error = "unknown error";
      }
      break;

    case SSH_KEYTYPE_OPENSSH_PEM:
    case SSH_KEYTYPE_OPENSSH_NEW:
    case SSH_KEYTYPE_SSHCOM:
      ssh2key = import_ssh2(infilename, intype, old_passphrase, &error);
      if (ssh2key) {
        if (ssh2key != SSH2_WRONG_PASSPHRASE)
          error = NULL;
        else
          error = "wrong passphrase";
      } else if (!error)
        error = "unknown error";
      break;

    default:
      assert(0);
    }

    if (error) {
      fprintf(stderr, "puttygen: error loading `%s': %s\n", infile, error);
      return 1;
    }
  }

  /*
   * Change the comment if asked to.
   */
  if (comment) {
    if (sshver == 1) {
      assert(ssh1key);
      sfree(ssh1key->comment);
      ssh1key->comment = dupstr(comment);
    } else {
      assert(ssh2key);
      sfree(ssh2key->comment);
      ssh2key->comment = dupstr(comment);
    }
  }

  /*
   * Unless we're changing the passphrase, the old one (if any) is a
   * reasonable default.
   */
  if (!change_passphrase && old_passphrase && !new_passphrase)
    new_passphrase = dupstr(old_passphrase);

  /*
   * Prompt for a new passphrase if we have been asked to, or if
   * we have just generated a key.
   */
  if (!new_passphrase && (change_passphrase || keytype != NOKEYGEN)) {
    prompts_t *p = new_prompts(NULL);
    int ret;

    p->to_server = FALSE;
    p->name = dupstr("New SSH key passphrase");
    add_prompt(p, dupstr("Enter passphrase to save key: "), FALSE);
    add_prompt(p, dupstr("Re-enter passphrase to verify: "), FALSE);
    ret = console_get_userpass_input(p, NULL, 0);
    assert(ret >= 0);
    if (!ret) {
      free_prompts(p);
      perror("puttygen: unable to read new passphrase");
      return 1;
    } else {
      if (strcmp(p->prompts[0]->result, p->prompts[1]->result)) {
        free_prompts(p);
        fprintf(stderr, "puttygen: passphrases do not match\n");
        return 1;
      }
      new_passphrase = dupstr(p->prompts[0]->result);
      free_prompts(p);
    }
  }
  if (new_passphrase && !*new_passphrase) {
    sfree(new_passphrase);
    new_passphrase = NULL;
  }

  /*
   * Write output.
   *
   * (In the case where outfile and outfiletmp are both NULL,
   * there is no semantic reason to initialise outfilename at
   * all; but we have to write _something_ to it or some compiler
   * will probably complain that it might be used uninitialised.)
   */
  if (outfiletmp)
    outfilename = filename_from_str(outfiletmp);
  else
    outfilename = filename_from_str(outfile ? outfile : "");

  switch (outtype) {
    int ret, real_outtype;

  case PRIVATE:
    if (sshver == 1) {
      assert(ssh1key);
      ret = saversakey(outfilename, ssh1key, new_passphrase);
      if (!ret) {
        fprintf(stderr, "puttygen: unable to save SSH-1 private key\n");
        return 1;
      }
    } else {
      assert(ssh2key);
      ret = ssh2_save_userkey(outfilename, ssh2key, new_passphrase);
      if (!ret) {
        fprintf(stderr, "puttygen: unable to save SSH-2 private key\n");
        return 1;
      }
    }
    if (outfiletmp) {
      if (!move(outfiletmp, outfile))
        return 1; /* rename failed */
    }
    break;

  case PUBLIC:
  case PUBLICO: {
    FILE *fp;

    if (outfile)
      fp = f_open(outfilename, "w", FALSE);
    else
      fp = stdout;

    if (sshver == 1) {
      ssh1_write_pubkey(fp, ssh1key);
    } else {
      if (!ssh2blob) {
        assert(ssh2key);
        ssh2blob = ssh2key->alg->public_blob(ssh2key->data, &ssh2bloblen);
      }

      ssh2_write_pubkey(fp,
                        ssh2key ? ssh2key->comment : origcomment,
                        ssh2blob,
                        ssh2bloblen,
                        (outtype == PUBLIC ? SSH_KEYTYPE_SSH2_PUBLIC_RFC4716
                                           : SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH));
    }

    if (outfile)
      fclose(fp);
  } break;

  case FP: {
    FILE *fp;
    char *fingerprint;

    if (sshver == 1) {
      assert(ssh1key);
      fingerprint = snewn(128, char);
      rsa_fingerprint(fingerprint, 128, ssh1key);
    } else {
      if (ssh2key) {
        fingerprint = ssh2_fingerprint(ssh2key->alg, ssh2key->data);
      } else {
        assert(ssh2blob);
        fingerprint = ssh2_fingerprint_blob(ssh2blob, ssh2bloblen);
      }
    }

    if (outfile)
      fp = f_open(outfilename, "w", FALSE);
    else
      fp = stdout;
    fprintf(fp, "%s\n", fingerprint);
    if (outfile)
      fclose(fp);

    sfree(fingerprint);
  } break;

  case OPENSSH_AUTO:
  case OPENSSH_NEW:
  case SSHCOM:
    assert(sshver == 2);
    assert(ssh2key);
    random_ref(); /* both foreign key types require randomness,
                   * for IV or padding */
    switch (outtype) {
    case OPENSSH_AUTO:
      real_outtype = SSH_KEYTYPE_OPENSSH_AUTO;
      break;
    case OPENSSH_NEW:
      real_outtype = SSH_KEYTYPE_OPENSSH_NEW;
      break;
    case SSHCOM:
      real_outtype = SSH_KEYTYPE_SSHCOM;
      break;
    default:
      assert(0 && "control flow goof");
    }
    ret = export_ssh2(outfilename, real_outtype, ssh2key, new_passphrase);
    if (!ret) {
      fprintf(stderr, "puttygen: unable to export key\n");
      return 1;
    }
    if (outfiletmp) {
      if (!move(outfiletmp, outfile))
        return 1; /* rename failed */
    }
    break;
  }

  if (old_passphrase) {
    smemclr(old_passphrase, strlen(old_passphrase));
    sfree(old_passphrase);
  }
  if (new_passphrase) {
    smemclr(new_passphrase, strlen(new_passphrase));
    sfree(new_passphrase);
  }

  if (ssh1key)
    freersakey(ssh1key);
  if (ssh2key) {
    ssh2key->alg->freekey(ssh2key->data);
    sfree(ssh2key);
  }

  return 0;
}

#ifdef TEST_CMDGEN

#undef main

#include <stdarg.h>

int passes, fails;

void setup_passphrases(char *first, ...)
{
  va_list ap;
  char *next;

  nprompts = 0;
  if (first) {
    prompts[nprompts++] = first;
    va_start(ap, first);
    while ((next = va_arg(ap, char *)) != NULL) {
      assert(nprompts < lenof(prompts));
      prompts[nprompts++] = next;
    }
    va_end(ap);
  }
}

void test(int retval, ...)
{
  va_list ap;
  int i, argc, ret;
  char **argv;

  argc = 0;
  va_start(ap, retval);
  while (va_arg(ap, char *) != NULL)
    argc++;
  va_end(ap);

  argv = snewn(argc + 1, char *);
  va_start(ap, retval);
  for (i = 0; i <= argc; i++)
    argv[i] = va_arg(ap, char *);
  va_end(ap);

  promptsgot = 0;
  ret = cmdgen_main(argc, argv);

  if (ret != retval) {
    printf("FAILED retval (exp %d got %d):", retval, ret);
    for (i = 0; i < argc; i++)
      printf(" %s", argv[i]);
    printf("\n");
    fails++;
  } else if (promptsgot != nprompts) {
    printf("FAILED nprompts (exp %d got %d):", nprompts, promptsgot);
    for (i = 0; i < argc; i++)
      printf(" %s", argv[i]);
    printf("\n");
    fails++;
  } else {
    passes++;
  }

  sfree(argv);
}

void filecmp(char *file1, char *file2, char *fmt, ...)
{
  /*
   * Ideally I should do file comparison myself, to maximise the
   * portability of this test suite once this application begins
   * running on non-Unix platforms. For the moment, though,
   * calling Unix diff is perfectly adequate.
   */
  char *buf;
  int ret;

  buf = dupprintf("diff -q '%s' '%s'", file1, file2);
  ret = system(buf);
  sfree(buf);

  if (ret) {
    va_list ap;

    printf("FAILED diff (ret=%d): ", ret);

    va_start(ap, fmt);
    vprintf(fmt, ap);
    va_end(ap);

    printf("\n");

    fails++;
  } else
    passes++;
}

char *cleanup_fp(char *s)
{
  char *p;

  if (!strncmp(s, "ssh-", 4)) {
    s += strcspn(s, " \n\t");
    s += strspn(s, " \n\t");
  }

  p = s;
  s += strcspn(s, " \n\t");
  s += strspn(s, " \n\t");
  s += strcspn(s, " \n\t");

  return dupprintf("%.*s", (int)(s - p), p);
}

char *get_fp(char *filename)
{
  FILE *fp;
  char buf[256], *ret;

  fp = fopen(filename, "r");
  if (!fp)
    return NULL;
  ret = fgets(buf, sizeof(buf), fp);
  fclose(fp);
  if (!ret)
    return NULL;
  return cleanup_fp(buf);
}

void check_fp(char *filename, char *fp, char *fmt, ...)
{
  char *newfp;

  if (!fp)
    return;

  newfp = get_fp(filename);

  if (!strcmp(fp, newfp)) {
    passes++;
  } else {
    va_list ap;

    printf("FAILED check_fp ['%s' != '%s']: ", newfp, fp);

    va_start(ap, fmt);
    vprintf(fmt, ap);
    va_end(ap);

    printf("\n");

    fails++;
  }

  sfree(newfp);
}

int main(int argc, char **argv)
{
  int i;
  static char *const keytypes[] = {"rsa1", "dsa", "rsa"};

  /*
   * Even when this thing is compiled for automatic test mode,
   * it's helpful to be able to invoke it with command-line
   * options for _manual_ tests.
   */
  if (argc > 1)
    return cmdgen_main(argc, argv);

  passes = fails = 0;

  for (i = 0; i < lenof(keytypes); i++) {
    char filename[128], osfilename[128], scfilename[128];
    char pubfilename[128], tmpfilename1[128], tmpfilename2[128];
    char *fp;

    sprintf(filename, "test-%s.ppk", keytypes[i]);
    sprintf(pubfilename, "test-%s.pub", keytypes[i]);
    sprintf(osfilename, "test-%s.os", keytypes[i]);
    sprintf(scfilename, "test-%s.sc", keytypes[i]);
    sprintf(tmpfilename1, "test-%s.tmp1", keytypes[i]);
    sprintf(tmpfilename2, "test-%s.tmp2", keytypes[i]);

    /*
     * Create an encrypted key.
     */
    setup_passphrases("sponge", "sponge", NULL);
    test(0, "puttygen", "-t", keytypes[i], "-o", filename, NULL);

    /*
     * List the public key in OpenSSH format.
     */
    setup_passphrases(NULL);
    test(0, "puttygen", "-L", filename, "-o", pubfilename, NULL);
    {
      char cmdbuf[256];
      fp = NULL;
      sprintf(
          cmdbuf, "ssh-keygen -l -f '%s' > '%s'", pubfilename, tmpfilename1);
      if (system(cmdbuf) || (fp = get_fp(tmpfilename1)) == NULL) {
        printf("UNABLE to test fingerprint matching against OpenSSH");
      }
    }

    /*
     * List the public key in IETF/ssh.com format.
     */
    setup_passphrases(NULL);
    test(0, "puttygen", "-p", filename, NULL);

    /*
     * List the fingerprint of the key.
     */
    setup_passphrases(NULL);
    test(0, "puttygen", "-l", filename, "-o", tmpfilename1, NULL);
    if (!fp) {
      /*
       * If we can't test fingerprints against OpenSSH, we
       * can at the very least test equality of all the
       * fingerprints we generate of this key throughout
       * testing.
       */
      fp = get_fp(tmpfilename1);
    } else {
      check_fp(tmpfilename1, fp, "%s initial fp", keytypes[i]);
    }

    /*
     * Change the comment of the key; this _does_ require a
     * passphrase owing to the tamperproofing.
     *
     * NOTE: In SSH-1, this only requires a passphrase because
     * of inadequacies of the loading and saving mechanisms. In
     * _principle_, it should be perfectly possible to modify
     * the comment on an SSH-1 key without requiring a
     * passphrase; the only reason I can't do it is because my
     * loading and saving mechanisms don't include a method of
     * loading all the key data without also trying to decrypt
     * the private section.
     *
     * I don't consider this to be a problem worth solving,
     * because (a) to fix it would probably end up bloating
     * PuTTY proper, and (b) SSH-1 is on the way out anyway so
     * it shouldn't be highly significant. If it seriously
     * bothers anyone then perhaps I _might_ be persuadable.
     */
    setup_passphrases("sponge", NULL);
    test(0, "puttygen", "-C", "new-comment", filename, NULL);

    /*
     * Change the passphrase to nothing.
     */
    setup_passphrases("sponge", "", "", NULL);
    test(0, "puttygen", "-P", filename, NULL);

    /*
     * Change the comment of the key again; this time we expect no
     * passphrase to be required.
     */
    setup_passphrases(NULL);
    test(0, "puttygen", "-C", "new-comment-2", filename, NULL);

    /*
     * Export the private key into OpenSSH format; no passphrase
     * should be required since the key is currently unencrypted.
     * For RSA1 keys, this should give an error.
     */
    setup_passphrases(NULL);
    test((i == 0),
         "puttygen",
         "-O",
         "private-openssh",
         "-o",
         osfilename,
         filename,
         NULL);

    if (i) {
      /*
       * List the fingerprint of the OpenSSH-formatted key.
       */
      setup_passphrases(NULL);
      test(0, "puttygen", "-l", osfilename, "-o", tmpfilename1, NULL);
      check_fp(tmpfilename1, fp, "%s openssh clear fp", keytypes[i]);

      /*
       * List the public half of the OpenSSH-formatted key in
       * OpenSSH format.
       */
      setup_passphrases(NULL);
      test(0, "puttygen", "-L", osfilename, NULL);

      /*
       * List the public half of the OpenSSH-formatted key in
       * IETF/ssh.com format.
       */
      setup_passphrases(NULL);
      test(0, "puttygen", "-p", osfilename, NULL);
    }

    /*
     * Export the private key into ssh.com format; no passphrase
     * should be required since the key is currently unencrypted.
     * For RSA1 keys, this should give an error.
     */
    setup_passphrases(NULL);
    test((i == 0),
         "puttygen",
         "-O",
         "private-sshcom",
         "-o",
         scfilename,
         filename,
         NULL);

    if (i) {
      /*
       * List the fingerprint of the ssh.com-formatted key.
       */
      setup_passphrases(NULL);
      test(0, "puttygen", "-l", scfilename, "-o", tmpfilename1, NULL);
      check_fp(tmpfilename1, fp, "%s ssh.com clear fp", keytypes[i]);

      /*
       * List the public half of the ssh.com-formatted key in
       * OpenSSH format.
       */
      setup_passphrases(NULL);
      test(0, "puttygen", "-L", scfilename, NULL);

      /*
       * List the public half of the ssh.com-formatted key in
       * IETF/ssh.com format.
       */
      setup_passphrases(NULL);
      test(0, "puttygen", "-p", scfilename, NULL);
    }

    if (i) {
      /*
       * Convert from OpenSSH into ssh.com.
       */
      setup_passphrases(NULL);
      test(0,
           "puttygen",
           osfilename,
           "-o",
           tmpfilename1,
           "-O",
           "private-sshcom",
           NULL);

      /*
       * Convert from ssh.com back into a PuTTY key,
       * supplying the same comment as we had before we
       * started to ensure the comparison works.
       */
      setup_passphrases(NULL);
      test(0,
           "puttygen",
           tmpfilename1,
           "-C",
           "new-comment-2",
           "-o",
           tmpfilename2,
           NULL);

      /*
       * See if the PuTTY key thus generated is the same as
       * the original.
       */
      filecmp(filename, tmpfilename2, "p->o->s->p clear %s", keytypes[i]);

      /*
       * Convert from ssh.com to OpenSSH.
       */
      setup_passphrases(NULL);
      test(0,
           "puttygen",
           scfilename,
           "-o",
           tmpfilename1,
           "-O",
           "private-openssh",
           NULL);

      /*
       * Convert from OpenSSH back into a PuTTY key,
       * supplying the same comment as we had before we
       * started to ensure the comparison works.
       */
      setup_passphrases(NULL);
      test(0,
           "puttygen",
           tmpfilename1,
           "-C",
           "new-comment-2",
           "-o",
           tmpfilename2,
           NULL);

      /*
       * See if the PuTTY key thus generated is the same as
       * the original.
       */
      filecmp(filename, tmpfilename2, "p->s->o->p clear %s", keytypes[i]);

      /*
       * Finally, do a round-trip conversion between PuTTY
       * and ssh.com without involving OpenSSH, to test that
       * the key comment is preserved in that case.
       */
      setup_passphrases(NULL);
      test(0,
           "puttygen",
           "-O",
           "private-sshcom",
           "-o",
           tmpfilename1,
           filename,
           NULL);
      setup_passphrases(NULL);
      test(0, "puttygen", tmpfilename1, "-o", tmpfilename2, NULL);
      filecmp(filename, tmpfilename2, "p->s->p clear %s", keytypes[i]);
    }

    /*
     * Check that mismatched passphrases cause an error.
     */
    setup_passphrases("sponge2", "sponge3", NULL);
    test(1, "puttygen", "-P", filename, NULL);

    /*
     * Put a passphrase back on.
     */
    setup_passphrases("sponge2", "sponge2", NULL);
    test(0, "puttygen", "-P", filename, NULL);

    /*
     * Export the private key into OpenSSH format, this time
     * while encrypted. For RSA1 keys, this should give an
     * error.
     */
    if (i == 0)
      setup_passphrases(NULL); /* error, hence no passphrase read */
    else
      setup_passphrases("sponge2", NULL);
    test((i == 0),
         "puttygen",
         "-O",
         "private-openssh",
         "-o",
         osfilename,
         filename,
         NULL);

    if (i) {
      /*
       * List the fingerprint of the OpenSSH-formatted key.
       */
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", "-l", osfilename, "-o", tmpfilename1, NULL);
      check_fp(tmpfilename1, fp, "%s openssh encrypted fp", keytypes[i]);

      /*
       * List the public half of the OpenSSH-formatted key in
       * OpenSSH format.
       */
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", "-L", osfilename, NULL);

      /*
       * List the public half of the OpenSSH-formatted key in
       * IETF/ssh.com format.
       */
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", "-p", osfilename, NULL);
    }

    /*
     * Export the private key into ssh.com format, this time
     * while encrypted. For RSA1 keys, this should give an
     * error.
     */
    if (i == 0)
      setup_passphrases(NULL); /* error, hence no passphrase read */
    else
      setup_passphrases("sponge2", NULL);
    test((i == 0),
         "puttygen",
         "-O",
         "private-sshcom",
         "-o",
         scfilename,
         filename,
         NULL);

    if (i) {
      /*
       * List the fingerprint of the ssh.com-formatted key.
       */
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", "-l", scfilename, "-o", tmpfilename1, NULL);
      check_fp(tmpfilename1, fp, "%s ssh.com encrypted fp", keytypes[i]);

      /*
       * List the public half of the ssh.com-formatted key in
       * OpenSSH format.
       */
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", "-L", scfilename, NULL);

      /*
       * List the public half of the ssh.com-formatted key in
       * IETF/ssh.com format.
       */
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", "-p", scfilename, NULL);
    }

    if (i) {
      /*
       * Convert from OpenSSH into ssh.com.
       */
      setup_passphrases("sponge2", NULL);
      test(0,
           "puttygen",
           osfilename,
           "-o",
           tmpfilename1,
           "-O",
           "private-sshcom",
           NULL);

      /*
       * Convert from ssh.com back into a PuTTY key,
       * supplying the same comment as we had before we
       * started to ensure the comparison works.
       */
      setup_passphrases("sponge2", NULL);
      test(0,
           "puttygen",
           tmpfilename1,
           "-C",
           "new-comment-2",
           "-o",
           tmpfilename2,
           NULL);

      /*
       * See if the PuTTY key thus generated is the same as
       * the original.
       */
      filecmp(filename, tmpfilename2, "p->o->s->p encrypted %s", keytypes[i]);

      /*
       * Convert from ssh.com to OpenSSH.
       */
      setup_passphrases("sponge2", NULL);
      test(0,
           "puttygen",
           scfilename,
           "-o",
           tmpfilename1,
           "-O",
           "private-openssh",
           NULL);

      /*
       * Convert from OpenSSH back into a PuTTY key,
       * supplying the same comment as we had before we
       * started to ensure the comparison works.
       */
      setup_passphrases("sponge2", NULL);
      test(0,
           "puttygen",
           tmpfilename1,
           "-C",
           "new-comment-2",
           "-o",
           tmpfilename2,
           NULL);

      /*
       * See if the PuTTY key thus generated is the same as
       * the original.
       */
      filecmp(filename, tmpfilename2, "p->s->o->p encrypted %s", keytypes[i]);

      /*
       * Finally, do a round-trip conversion between PuTTY
       * and ssh.com without involving OpenSSH, to test that
       * the key comment is preserved in that case.
       */
      setup_passphrases("sponge2", NULL);
      test(0,
           "puttygen",
           "-O",
           "private-sshcom",
           "-o",
           tmpfilename1,
           filename,
           NULL);
      setup_passphrases("sponge2", NULL);
      test(0, "puttygen", tmpfilename1, "-o", tmpfilename2, NULL);
      filecmp(filename, tmpfilename2, "p->s->p encrypted %s", keytypes[i]);
    }

    /*
     * Load with the wrong passphrase.
     */
    setup_passphrases("sponge8", NULL);
    test(1, "puttygen", "-C", "spurious-new-comment", filename, NULL);

    /*
     * Load a totally bogus file.
     */
    setup_passphrases(NULL);
    test(1, "puttygen", "-C", "spurious-new-comment", pubfilename, NULL);
  }
  printf("%d passes, %d fails\n", passes, fails);
  return 0;
}

#endif
